What is the difference between a Barlow lens and an erecting eyepiece?
If you use a 2x Barlow lens with an eyepiece, the magnification doubles. In an astronomical telescope, the image is laterally transposed and/or upside down. This is unimportant for astronomical observing, but for terrestrial observing it is important. Erecting lenses provide an upright and true-sided image.
Where is erecting lens used?
An eyepiece sometimes used in Kepler telescopes that consists of four lenses and provides an erect image, which is more convenient for viewing terrestrial objects than the inverted image provided by simpler eyepieces.
What is an erecting eyepiece on a telescope?
An erect image eyepiece is a series of prisms combined with eyepiece lenses designed to rotate the image from a telescope’s main optics by 180°. It’s most commonly used with the Newtonian reflector. It simply replaces whatever eyepiece you would normally use.
What is a Plossl eyepiece?
Steve says: “A Plössl eyepiece comprises four glass elements arranged as two back-to-back achromatic doublets; or, in other words, two pairs of two glass lenses. Advertisement. These eyepieces produce a ‘standard apparent feld of view’ of between 50° and 56° with most set at around 52°.
What is the magnification of terrestrial telescope?
The magnifying power of terrestrial telescope is 25 when it is in normal adjustment and the length of the telescope is 124 cm. If the focal length of the erecting lens is 5 cm, the focal lengths of the objective and the eye-piece are respectively.
What is erecting prism used for?
A star diagonal, erecting lens or diagonal mirror is an angled mirror or prism used in telescopes that allows viewing from a direction that is perpendicular to the usual eyepiece axis.
What size eyepiece do I need to see the moon?
Short focal length (5-10mm) eyepieces provide high power magnifications and are best for observing the planets and the moon on medium focal length telescopes.
What’s up with the stoned edge of the eyepiece?
The stoned edge of the eye-lens… That will need some attention, along with the others within. This is the most curious feature of the eyepiece… There appears to be a prismatic something or other peeking through that retaining assembly; and what’s up with those two white tabs.
What size eyepieces should I buy for my scope?
A general rule to calculate the scope’s maximum magnification is take the aperture and multiply by 2 (76 x 2 = 152) so in your case you should only buy eyepieces that provide no more than x152 magnification. So what is the range of eyepiece sizes available for your scope?
When to use the erecting prism on a scope?
The 1.5x erecting prism will be used when using the scope for terrestrial objects to make the view the right way up. No need to use this for astronomy targets as it does not matter what way up these are. More sharing options…
What is the best eyepiece for astronomy?
As Paul says, for astronomy use, the upside down view is the one to get used to as the erecting eyepiece will detract from the quality of the view. Astro scopes generally won’t focus on things closer than 50-100 feet away, sometimes further than that. Try using just the 20mm eyepiece to start with and then try the barlow with that eyepiece.